Osmo-FL2K stops transmitting randomly

Steve Markgraf steve at steve-m.de
Wed Jun 13 19:13:00 UTC 2018

Hi Sajjad,

On 13.06.2018 20:38, Sajjad Golchin poor wrote:
> as some of you know Osmo-fl2k has a bothersome software issue that
> sometimes just stop transmitting without any good reason. in my case
> when I was transmitting WBFM sometimes it may stop transmitting. I mean
> the RF output will be interrupted completely without any error or
> warnings on screen and I should re-execute the commands to transmit
> again and this goes on and on. sometimes it may work without any issues
> for like 10 min and sometimes it may fail after just a few seconds. the
> problem also appeared in executing <fl2k_file> when I was transmitting
> DVB-T.
> you can watch this video to gain a better understanding:
> https://www.youtube.com/watch?v=G0tjzPHFFA8

This will happen if the host cannot supply enough data to the device,
you need to use a lower sample rate in this case, or get rid of
a hypervisor like VMware, as is the case in this video.

When operating as a normal graphics adapter, the frame would be skipped
when an underflow happens and the screen flickers, however, when
HSYNC/VSYNC is disabled the device completely stops and needs to be
There seems to be a 'frame loss' mechanism to detect this in  through an
interupt transfer, but I haven't implemented this yet and have no idea
if this works with disabled synchronization.

Anyway, there seems to be something wrong with your setup. Either host
controller, or host controller driver etc. What setup are you using (OS,
host controller, any virtualization present like in the video?)


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